First terrestrial occurrence of the complex phosphate chladniite: crystal-structure refinement by synchrotron through-the-substrate microdiffraction
Chladniite, a complex phosphate species belonging to the fillowite group so far only found in meteorites, was identified in a pegmatite from Córdoba (Argentina) as inclusions in beusite. Applying synchrotron through-the-substrate microdiffraction technique to polished thin sections prepared on very...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2017 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/44761 |
| Acceso en línea: | http://hdl.handle.net/11336/44761 |
| Access Level: | acceso abierto |
| Palabra clave: | Tts-M Xrd Complex Phosphates Fillowite Group Meteorites Pegmatites https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 |
| Sumario: | Chladniite, a complex phosphate species belonging to the fillowite group so far only found in meteorites, was identified in a pegmatite from Córdoba (Argentina) as inclusions in beusite. Applying synchrotron through-the-substrate microdiffraction technique to polished thin sections prepared on very thin glass-substrates (0.1 mm), diffraction data with nearly single-crystal quality were directly measured at selected chladniite microvolumes of the section. Chladniite is trigonal (space group R-3), with a = 15.0133(3) Å, c = 42.887(2) Å, V = 8371.6(5)Å3. The subsequent crystal-structure refinement confirms that the accuracy attainable by using 0.1-mm-thick glass-substrates is comparable to that of routine single-crystal measurements [R1 = 3.34% for 1617 unique reflections]. The refined crystal structure of pegmatitic chladniite differs from the meteoritic one in the cation ordering (Mg, FeþMn and Ca) at the various metal sites, with Mn being dominant at the M(1) position. |
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